public string ConsumeCharacterReference(char?additionalAllowedCharacter, bool inAttribute)
{
if (reader.IsEmpty)
{
return(null);
}
if (additionalAllowedCharacter.HasValue && additionalAllowedCharacter.Value == reader.Current)
{
return(null);
}
if (reader.MatchesAny('\t', '\n', '\f', ' ', '<', '&'))
{
return(null);
}
reader.Mark();
if (reader.MatchConsume("#")) // numbered
{
bool isHexMode = reader.MatchConsumeIgnoreCase("X");
string numRef = isHexMode ? reader.ConsumeHexSequence() : reader.ConsumeDigitSequence();
if (numRef.Length == 0) // didn't match anything
{
ParseError.NumericReferenceWithNoNumerals(this);
reader.RewindToMark();
return(null);
}
if (!reader.MatchConsume(";"))
{
ParseError.MissingSemicolon(this);
}
int charval = -1;
try {
int base2 = isHexMode ? 16 : 10;
charval = Convert.ToInt32(numRef, base2);
} catch (FormatException) {
} // skip
if (charval == -1 || (charval >= 0xD800 && charval <= 0xDFFF) || charval > 0x10FFFF)
{
ParseError.CharOutsideRange(this);
return(replacementStr);
}
else
{
// TODO: implement number replacement table
// TODO: check for extra illegal unicode points as parse errors
return(Char.ConvertFromUtf32(charval));
}
}
else // named
// get as many letters as possible, and look for matching entities. unconsume backwards till a match is found
{
string nameRef = reader.ConsumeLetterThenDigitSequence();
string origNameRef = nameRef; // for error reporting. nameRef gets chomped looking for matches
bool looksLegit = reader.Matches(';');
bool found = false;
while (nameRef.Length > 0 && !found)
{
if (HtmlEncoder.IsNamedEntity(nameRef))
{
found = true;
}
else
{
nameRef = nameRef.Substring(0, nameRef.Length - 1);
reader.Unconsume();
}
}
if (!found)
{
if (looksLegit) // named with semicolon
{
ParseError.InvalidNamedReference(this, origNameRef);
}
reader.RewindToMark();
return(null);
}
if (inAttribute && (reader.MatchesLetter() || reader.MatchesDigit() || reader.MatchesAny('=', '-', '_')))
{
// don't want that to match
reader.RewindToMark();
return(null);
}
if (!reader.MatchConsume(";"))
{
ParseError.MissingSemicolon(this);
}
return(HtmlEncoder.GetCharacterByName(nameRef));
}
}